O/D Off light blinking P0715 code

CONTOURCONFOUNDED

2006 FORD CONTOUR

4 CYL

FWD

AUTOMATIC

80,000 MILES

I have a 1996 (80k mi.) Ford Contour, 4cyl, 2.0L with CD4E automatic transaxle. The O/D Off light began blinking while driving on the highway, and the tranaxle downshifted to 3rd gear. The check engine code was P0715 indicating a faulty TSS sensor or circuit. Specifically, the code indicates a >15 mph vehicle speed with a <60 rpm transmission shaft speed, or electrical problem. I replaced the transmission (turbine) speed sensor sensor and the vehicle speed sensor, but these have not solved the problem. The O/D Off light continues to blink, the car shifts roughly between gears 1-2-3, and the 4th gear is locked out. I checked for and open condition between the PCM, TSS and CMP wiring, but there is little resistance. I do not know how to check for a short, but the wiring does not look bad except for exposed wires at some of the sensor connectors that are close to the block and sometimes have cracked insulation on one or more wires. Should I still suspect the wiring for a short, suspect a PCM malfunction, or is there another reason this code would be displayed? I've checked the code multiple times with no variation, and the light comes on at low speed (10-15mph) which seems to indicate a sensor issue, not a mechanical problem with the transaxle.

Also, the car died serveral time recently when accellerating from an idle. This also occured around 9 months ago. I don't believe this is part of the problem above, because the car generally runs rough at an idle, and hesitates at the initial accelleration. But if the PCM is suspect, then this could be relevant.